Monday, January 1, 2018

Research @ Otago - Erica Donlon

Erica is studying growth, development rates, and ageing methods in the midget octopus, Octopus huttoni.

Erica taking measurements of a common octopus

Erica is currently breeding wild caught midget octopus from Otago and the Foveaux Strait. Once females lay their eggs in a small crevice or tube, they will starve for the entire gestation period (30-80 days) in order to protect the eggs and keep them clean of debris.

Midget octopus with eggs
When the eggs hatch, the paralarvae live in the plankton for 40-70 days feeding on crab larvae and absorbing nutrients through the skin. In Erica's experiment, the paralarvae will be reared in 4 temperatures (5°, 11°, 17°, and 23°C) to observe how ocean warming could have an effect on the developmental rates of these octopus.

Midget octopus paralarvae
The white ball seen beneath the eyes and between the tentacles is a yolk sac that will be quickly consumed as they start swimming in the water column.

Paralarvae starting to hatch
During the next year, Erica will be observing the growth rates of this species by looking at growth rings on the beaks and stylets (remnant of the mollusc shell). This new information will give more insight of the life history of this species which can then be applied to other pygmy octopus species.

Wednesday, October 4, 2017

Research @ Otago - Rebecca McMullin

Rebecca’s research focuses on tracking the flow and fate of waste materials from salmon farms through food webs in the Marlborough Sounds.

Salmon aquaculture involves the input of large quantities of feed into sea farms, which in turn results in the production of organic and nutrient wastes that have the effect of increasing the ecological footprints of the farm. This may have consequences for the connectivity of food webs within the farm's ecological footprint.

Bagging and labelling samples
With help from a team of researchers in the Department of Marine Science, Rebecca has collected key species of fish, macroinvertebrates and benthic infauna (small invertebrates that live in the sediment) from around salmon farms in the Marlborough Sounds. These samples are now being processed and analysed to determine the proportion of organic matter each organism sources from farm waste relative to the proportion they source from natural marine sources such as macroalgae and phytoplankton.
Collecting samples from a salmon farm in the Marlborough Sounds
Rebecca has also set up mesocosms (like miniature ecosystems) at Portobello Marine Laboratory that will allow us to measure parameters that are useful for modelling the real-world system in the Marlborough Sounds.
Mesocosm set up at the Portobello Marine Laboratory
Ultimately this research will be useful in minimising negative impacts of aquaculture on natural ecosystems.

Wednesday, September 6, 2017

Research @ Otago - Daniel Smart

Daniel’s research focuses on understanding one of the most pivotal aspects of an organism, its reproductive cycle, and how a warming ocean will affect the development of larvae. 

Daniel is working on the blue mussel (Mytilus galloprovincialis), a species in New Zealand for which there are large knowledge gaps. Trying to fill these knowledge gaps is of importance as blue mussels are significant organisms, having key roles in coastal marine ecosystems.
Daniel is investigating the timings of the reproductive cycle by taking monthly samples and looking at which stage they are at in their reproductive cycle. This will be carried out over a 12-month period, enabling an understanding of the timings of the reproductive cycle.   
Blue mussel open ready for dissection
Daniel is also looking at how blue mussel larvae will respond to a warming ocean, with experiments being run using different temperature treatments, and assessing the impacts of these different temperatures on the development and survival of the larvae.

Thursday, January 19, 2017

Research @ Otago - Nadjejda Espinel

Nadjejda is studying the effects of climate change on marine ecosystems, and marine invertebrates in particular.   

Nadjejda raises the microscopic larvae in the laboratory
Nadjejda's research focuses on the effects of ocean acidification and warming on the larval settlement of some New Zealand key species including paua, kina, barnacles (Austrominius modestus) and polychaetes (Galeolaria hystrix), trying to understand how these species will fare in future acidified and warmed-up oceans.
The approximate size of the Nauplius larvae is 0.5mm
Most of the sessile  (organisms that live attached to the substrate) and benthic marine invertebrates spawn planktonic larvae into the water column. These larvae swim freely until they find a place appropriate to spend their adult lives and then they settle and metamorphose - this is what we call the settlement process. Any factors influencing the settlement process might influence the future distribution of species and ultimately the diversity of the marine ecosystems.  The settlement process could be influenced by direct changes in the larval physiology, or by indirect changes in the settlement substrates.
Nadjejda collecting adult barnacles from the rocks at Portobello Marine Laboratory
In order to study this, Nadjejda collects invertebrates (adults), spawns them and rears the larvae in the lab, in order to get them to settle. The core of her research comprises experiments in the lab trying to settle larvae in different pH treatments on different types of substrates, in order to see whether a significant effect can be expected at the future predicted levels of acidification and warming.

Thursday, August 11, 2016

Research @ Otago - Rob Lewis

Rob is working on a system to identify individual Sevengill sharks so New Zealand's Sevengill shark populations can be catalogued for future study and analysis.

Many of our local species of sharks are lesser known or unheard of in New Zealand as is the case in the Sevengill shark (Notorynchus cepedianus).  Sevengill sharks are important coastal predators that help regulate the health our local marine ecosystems. There are, however, large gaps of knowledge pertaining to the basic parameters of Broadnose Sevengill population size, composition, life span, growth rates, sexual maturity and vulnerability to fishing pressures in New Zealand.

Through the use of baited underwater camera stations we can identify each individual Sevengill encountered and start getting to know some of these missing characteristics of the NZ population. Rob's study focuses on a population of Sevengill sharks in Paterson Inlet, Stewart Island, that exhibits an all-year-round presence. The use of baited remote video systems to sample this population is ideal as they are a non-invasive, repeatable, cost-effective and easy to deploy. 

Once there is a catalogue of individuals it will be possible to start characterising the Paterson Inlet population demographics including abundance, estimated population size, sex ratio, size ranges and maturity. Only with these data present and accurate can sensible and effective future management decisions be made regarding the species.

Sunday, April 17, 2016

Research @ Otago - Kate Sparks

Kate is studying Antarctic starfish - What can they tell us about how polar marine life may adapt to a warmer world?

The Antarctic seas are among the fastest warming and acidifying waters on the planet, and the animals living there need to adapt - or face becoming vulnerable to extinction. Antarctic sea stars, which are important 'keystone' species in their ecosystems, can tell us a lot about the responses of polar marine species to ocean warming and acidification.

Kate checking out the seastar specimens in the lab at Scott Base

Kate Sparks has been working with the Antarctic cushion star to characterise the adaptive capacity and genetic variation within the wild population in response to warmer and acidified conditions. This is an important step in understanding the potential consequences of global ocean change on marine life in Antarctica.

Penguins - although not the species studied by Kate, they are very photogenic!

Tuesday, September 8, 2015

Research @ Otago - Tyler Northern

Tyler is studying the mineral make up of statoliths (a hard structure that works as a gravity receptor) from warty squid (Onykia ingens).

I am working closely with a group at the ALCES lab at AUT run by Dr Kathrin Bolstad who also study cephalopods (squid and octopus) around NZ.  As a result, I have recently been on a trawl survey with NIWA on their research vessel, the Tangaroa. I spent three and a half weeks living aboard the Tangaroa on the Chatham Rise in August 2015 and my job was to identify and collect cephalopods.
The RV Tangaroa docked in Lyttleton, Christchurch (Photo: Nathania Brooke)

Being aboard the Tangaroa was an amazing experience, I met lots of really easy going people and we were fed very well! We were targeting mid-trophic level organisms which means we wanted to catch the things that big fish eat, although we did get a few big fish! We measured and weighed all of the fish we caught and took stomach and tissue samples from a sub-sample of them to be analysed at NIWA.
Tyler with a 18kg Ling caught and sampled on the Chatham Rise

We also caught a lot of cool squid including my study animal! 

A mature warty squid (Onykia ingens) hauled up from the depths

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